so i was just curious on two subwoofer cab designs i have one is from the proven turbosound tsw 718 ad the other is from another unfinished website for speaker designs. i Really curious on your guys input of the ported vs unported design

matthias... you need to fix your links or better still if they are just images is to upload them directly

Too add a photo.

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so i was just curious on two subwoofer cab designs i have one is from what i believe is the proven turbosound tsw 718 the other is from another unfinished website for speaker designs. i Really curious on your guys input of the ported vs unported design for a horned sub box.

hi matthias
wel you have to simulate the driver to see if it works in each cab.
the ports in the left design is to limmit excusion at port tuning frequentie.
below that excursion rizes rapidly.
both are bandpass horns ,i guestimate the wil rol off at 50 or so ,looking at the short horn.
they wil be verry efficient.

__________________one good thing about music ,when it hit you feel no pain.
so hit me with music.hr driver db

Ported horns are used for a long time. The ports are usually used to extend the bandwidth (bandpass) of such horn. An issue that should be considered with ported horns is that the excursion at the lowest part of the bandpass (there were the port is active) increases considerably.

What happens is that the efficiency of horn is traded for the less efficient port to give it a low end extension. Less efficient means that the driver needs to work harder to keep up with the rest of the horn-design. For instance, if you would use the same driver/concept of the Turbo Sound you mentioned and you would add a port, the frequency range (bandpass) could be extended but at cost of higher excursion. In practice that would mean the PD driver would run out of excursion very soon.

Tapped Horns also have two sides of the cone loaded. Therefore you can kind off compare them with ported horns. The difference is that Tapped Horns (sometimes described as a tapped pipe) have both sides of the cone loaded by the same horn/pipe. Since horns or pipes (both quarter wavelength resonators) are more efficient than ports (half wavelength resonator), the tapped horn becomes more efficient in the low end compared to ported horns. More efficient means lower excursion so the Tapped Horn will have more output in the lowest part of the bandpass, compared to a ported horn.The downside is that higher up the bandpass the 'true horn' of a ported horn becomes more efficient than the tapped horn.

In classic designs like the Nexo 1000 and 2000 range for instance, they also made use of a ported horn design. To prevent the excursion from going too extreme they made the ports smaller in diameter. In practice that would mean that the ports run into compression at high levels to prevent extreme excursion. This is a designer trick that needs careful study to make it work correctly. One needs to design for a specific driver and lots of testing needs to be done. The downside of this trick is that at high levels the low end stays behind. It works like a kind of dynamic EQ but than in a mechanical way.

So the turbo sound design would be more efficient with less excursion? but the ported design could reach lower tuning freq more easily but at the cost of higher excursion risking the life of the driver?

"So the turbo sound design would be more efficient with less excursion? but the ported design could reach lower tuning freq more easily but at the cost of higher excursion risking the life of the driver"
Yes, that is right.

That is the reason why you see relative high tunings for so called ‘hybrid-horns’ (relative short horns with basreflex ports). Usually these basreflex port(s) are tuned at or above 50Hz for conventional 18" drivers.

although the dynamic sound of a tru bashorn is almost unsurpassed,nowadays ,with the power cheaply available,its not realy nessecerry anymore.(imho)
a horn to 35 hz needs to be realy big(i,m talking thousands of liters)
you could always compromise/truncade the horn,and stack them but its still gona be big.
this is why the tapped horns are popular her at the diyaudio.
more efficient as bassreflex and much smaller then a front loaded horn.
if you still want to go for a flh ,you need to decide on driver type and see what you can do with it in simulation.
e

__________________one good thing about music ,when it hit you feel no pain.
so hit me with music.hr driver db